The purpose of this study is to identify risk factors for periodontitis associated with HIV infection and to develop risk assessment models of periodontal disease in HIV infected patients. Periodontal disease affects a majority of the HIV seropositive individuals, and millions of dollars per year required to treat existing disease. It has been suggested that HIV infected individuals are at higher risk than others for the development of periodontal disease. Although previous studies by several groups in addition to ourselves have associated environmental and host factors with destructive periodontal diseases, there is a lack of information related to the risk factors and risk assessment models of periodontitis in HIV infected individuals. The specific aims are: 1) investigate the associations between biochemical components of gingival crevicular fluid (GCF), periodontopathic bacteria and clinical measures of periodontal disease in HIV infected individuals, 2) investigate the associations between immunological parameters, demographic variables, and clinical measures of periodontal status, and 3) construct risk assessment models of periodontal disease in HIV infected individuals. A longitudinal study of 225 HIV infected volunteers from the HIV CARE clinic at the University of the Pacific School of Dentistry serving a diverse HIV population (i.e. Whites, African-Americans, Hispanics, and Asians) will be performed to identify risk factors for periodontal disease over a six-month period. Study subjects will be seen at baseline and 6 month visits. Immunological variables, medical status, demographic variables and clinical measures of periodontal disease will be recorded. GCF and subgingival plaque samples will be collected from mesiobuccal sites of 4 lower incisors and upper right (or upper left) posterior sextant in each subject. By identifying the risk factors for periodontal disease, high risk individuals can be targeted and preventive measures can be taken to intercept the disease process with therapy.